Operations, such as surveying, drilling, wireline testing, completions, production, planning and field analysis, are typically performed to locate and gather valuable downhole fluids. Surveys are often performed using acquisition methodologies, such as seismic scanners or surveyors to generate maps of underground formations. These formations are often analyzed to determine the presence of subterranean assets, such as valuable fluids or minerals, or to determine if the formations have characteristics suitable for storing fluids. Although the subterranean assets are not limited to hydrocarbon such as oil, throughout this document, the terms “oilfield” and “oilfield operation” may be used interchangeably with the terms “field” and “field operation” to refer to a field having any types of valuable fluids or minerals and field operations relating to any of such subterranean assets.
Petroleum system models can predict if, and how, a reservoir has been charged with hydrocarbons, including the source and timing of hydrocarbon generation, migration routes, quantities, and hydrocarbon type. Petroleum system models include the quantitative analysis and simulation of geological processes in sedimentary basins on a geological timescale. It further encompasses geometric development of the basin, heat and pore water flow modeling with regard to sediment compaction and basin subsidence or uplift, and the temperature-controlled chemistry of mineral and organic matter changes. Petroleum system models may be used to simulate processes related to the generation, migration, accumulation and loss of oil and gas, thereby leading to an improved understanding and predictability of their distribution and properties.
Geomechanics is the science of the way rocks compress, expand, and fracture. Over the geological timescale of a prospect or play, sediments are deposited, compacted, lithified, and deformed by tectonic events to produce layers of rocks with highly anisotropic and nonlinear mechanical characteristics. Where reservoirs exist, the fluids they contain, the reservoir rocks themselves, and the formations that surround them form intimately coupled systems.
Geomechanical models use calculated pressure, temperature, and saturation to calculate the behavior of the formation rock through geologic time. By relating rock stresses to reservoir properties, the geomechanical model enables the development of mechanical earth models that predict the geomechanical behavior of the formation during production and injection. The removal of hydrocarbons from a reservoir or the injection of fluids changes the rock stresses and geomechanics environment, potentially affecting compaction and subsidence, well and completion integrity, cap-rock and fault-seal integrity, fracture behavior, thermal recovery, and carbon dioxide disposal. Further, geomechanical models can provide faults stability and reactivation information throughout geological time, which is important for hydrocarbon migration and accumulation analysis.